Mobile terminals such as mobile phones are spreading throughout our daily lives due to their excellent convenience. Users in possession of mobile terminals can make telephone calls from any area. Mobile terminals are equipped with various kinds of functions in addition to the phone function, and the variety of the functions is increasing. Recent mobile terminals are equipped with functions for communicating by radio waves, such as E-mails, the Internet, and videophones.
Radio wave reception levels of a mobile terminal will vary depending on the location. For example, in most cases, radio waves of a mobile terminal are weaker inside buildings and apartments, and stronger outside. Because radio wave reception levels vary depending on the location, the reception level may not always be high where a user uses a mobile terminal. Accordingly, the user needs to check whether the reception level is high or not where the user will use the mobile terminal before the user uses communication services, such as a telephone call, E-mail, the Internet, and videophone, with the mobile terminal. If the radio wave reception level of the mobile terminal is not high, the user has to move to a location where the radio wave reception level is high. However, the user cannot determine a location where the radio wave reception level is high as desired, and therefore, the user needs to search for a location while moving around and checking the radio wave reception level displayed on the mobile terminal.
In order to solve such a problem, one method that has been proposed notifies a user of a location where the radio wave reception level is high. Patent reference 1 discloses a radio quality display system and method. FIG. 9 is a schematic diagram of the radio quality display system disclosed in patent reference 1. In the radio quality display system shown in FIG. 9, a user inputs a request for high reception level position information through an operation panel of a mobile terminal 302. The mobile terminal 302 then transmits area identification information, radio wave reception levels from base stations 303a and 303b, and current position information from a GPS (Global Position System) to a radio quality server 307 via the base stations 303a, 303b and a mobile switching network 304. The radio quality server 307 has a database that stores the quality distribution concerning the received area identification information, the received radio wave reception levels, and the received current position information, and extracts from the database a position with a reception level higher than that of the current position of the mobile terminal 302. Thereafter, the radio quality server 307 calculates the direction and the distance from the mobile terminal 302 to the extracted position, and transmits the calculated result to the mobile terminal 302 as high reception level position information. The mobile terminal 302 then displays the high reception level position information received from the radio quality server 307. FIG. 10 shows an example of the high reception level position information displayed on a screen 321. In FIG. 10, the high reception level position information 322 is expressed by a direction and a distance. The user moves to a location in accordance with the high reception level position information 322 displayed on the screen 321 of the mobile terminal 302. The user can thus use communication services at a location where the radio wave reception level is high.
Patent Reference 1: Japan Published Patent Application No. 2003-199158